The 2001 anthrax attacks, also known as Amerithrax (a portmanteau of "America" and "anthrax", from its FBI case name), occurred in the United States over the course of several weeks beginning on September 18, 2001, one week after the September 11 attacks. Letters containing anthrax spores were mailed to several news media offices and to senators Tom Daschle and Patrick Leahy, killing five people and infecting seventeen others. Capitol police officers and staffers working for Senator Russ Feingold were exposed as well. According to the FBI, the ensuing investigation became "one of the largest and most complex in the history of law enforcement". They are the only lethal attacks to have used anthrax outside of warfare.
The FBI and CDC authorized Iowa State University to destroy its anthrax archives in October 2001, which hampered the investigation. In the following weeks, US officials and media unsuccessfully attempted to link the attacks to Al-Qaeda and/or Ba'athist Iraq. Thereafter, a major focus in the early years of the investigation was bioweapons expert Steven Hatfill, who was eventually exonerated. Bruce Edwards Ivins, a scientist at the government's biodefense labs at Fort Detrick in Frederick, Maryland, became a focus around April 4, 2005. On April 11, 2007, Ivins was put under periodic surveillance and an FBI document stated that he was "an extremely sensitive suspect in the 2001 anthrax attacks". On July 29, 2008, Ivins died by suicide with an overdose of acetaminophen (paracetamol).
Federal prosecutors declared Ivins the sole perpetrator on August 6, 2008, based on DNA evidence leading to an anthrax vial in his lab. Two days later, Senator Chuck Grassley and Representative Rush D. Holt Jr. called for hearings into the Department of Justice and FBI's handling of the investigation. The FBI formally closed its investigation on February 19, 2010.
In 2008, the FBI requested a review of the scientific methods used in their investigation from the National Academy of Sciences, which released their findings in the 2011 report Review of the Scientific Approaches Used During the FBI's Investigation of the 2001 Anthrax Letters. The report cast doubt on the government's conclusion that Ivins was the perpetrator, finding that the type of anthrax used in the letters was correctly identified as the Ames strain of the bacterium, but that there was insufficient scientific evidence for the FBI's assertion that it originated from Ivins' laboratory.
The FBI responded by saying that the review panel asserted that it would not be possible to reach a definite conclusion based on science alone, and said that a combination of factors led the FBI to conclude that Ivins had been the perpetrator. Some information is still sealed concerning the case and Ivins' mental health. The government settled lawsuits that were filed by the widow of the first anthrax victim Robert Stevens for $2.5 million with no admission of liability. The settlement was reached solely for the purpose of "avoiding the expenses and risks of further litigations", according to a statement in the agreement.
Context
The anthrax attacks began a week after the 9/11 attacks, which had caused the destruction of the original World Trade Center in New York City, damage to the Pentagon in Arlington, Virginia, and the crash of an airliner in an empty field in Shanksville, Pennsylvania. The anthrax attacks came in two waves. The first set of letters containing anthrax had a Trenton, New Jersey, postmark dated September 18, 2001. Five letters are believed to have been mailed at this time to ABC News, CBS News, NBC News and the New York Post, all located in New York City, and to the National Enquirer at American Media, Inc., (AMI) in Boca Raton, Florida.
The first known victim of the attacks, Robert Stevens, who worked at the Sun tabloid, also published by AMI, died on October 5, 2001, four days after entering a Florida hospital with an undiagnosed illness that caused him to vomit and be short of breath. The presumed letter containing the anthrax which killed Stevens was never found. Only the New York Post and NBC News letters were actually identified; the existence of the other three letters is inferred because individuals at ABC, CBS and AMI became infected with anthrax. Scientists examining the anthrax from the New York Post letter said it was a clumped coarse brown granular material which looked similar to dog food.
Two more anthrax letters, bearing the same Trenton postmark, were dated October 9, three weeks after the first mailing. The letters were addressed to two U.S. senators, Tom Daschle of South Dakota and Patrick Leahy of Vermont. At the time, Daschle was the Senate majority leader and Leahy was head of the Senate Judiciary Committee; both were members of the Democratic Party. The Daschle letter was opened by an aide, Grant Leslie, on October 15, after which the government mail service was immediately shut down.
Twenty-eight staffers working in Senate offices in the Hart Senate Office Building tested positive for anthrax exposure after the letter was opened, including staffers from adjoining suites in Sen. Russell Feingold of Wisconsin's office. Navy infectious disease specialist Greg Martin, who treated the Senate staffers, prescribed a two-month course of Ciprofloxacin antibiotics for the exposed staffers, none of whom were sickened by the exposure.
The unopened Leahy letter was discovered in an impounded mailbag on November 16. The Leahy letter had been misdirected to the State Department mail annex in Sterling, Virginia, because a ZIP Code was misread; a postal worker there, David Hose, contracted inhalational anthrax.
More potent than the first anthrax letters, the material in the Senate letters was a highly refined dry powder consisting of about one gram of nearly pure spores. A series of conflicting news reports appeared, some claiming the powders had been "weaponized" with silicon dioxide. Bioweapons experts who later viewed images of the anthrax used in the attacks saw no indication of "weaponization". Tests at Sandia National Laboratories in early 2002 confirmed that the attack powders were not weaponized.
At least 22 people developed anthrax infections, 11 of whom contracted the especially life-threatening inhalational variety. Five died of inhalational anthrax: Stevens; two employees of the Brentwood mail facility in Washington, D.C. (Thomas Morris Jr. and Joseph Curseen), and two whose source of exposure to the bacteria is still unknown: Kathy Nguyen, a Vietnamese immigrant resident of the New York City borough of the Bronx who worked in the city, and the last known victim, Ottilie Lundgren, a 94-year-old widow of a prominent judge from Oxford, Connecticut.
Because it took so long to identify a culprit, the 2001 anthrax attacks have been compared to the Unabomber attacks which took place from 1978 to 1995.
Letters
Authorities believe that the anthrax letters were mailed from Princeton, New Jersey. Investigators found anthrax spores in a city street mailbox located at 10 Nassau Street near the Princeton University campus. About 600 mailboxes which could have been used to mail the letters were tested for anthrax, and the Nassau Street box was the only one to test positive.
The New York Post and NBC News letters contained the following note:
The second note was addressed to Senators Daschle and Leahy and read:
09–11–01
YOU CAN NOT STOP US.
WE HAVE THIS ANTHRAX.
YOU DIE NOW.
ARE YOU AFRAID?
DEATH TO AMERICA.
DEATH TO ISRAEL.
ALLAH IS GREAT.
All of the letters were copies made by a copy machine, and the originals were never found. Each letter was trimmed to a slightly different size. The Senate letter uses punctuation, while the media letter does not. The handwriting on the media letter and envelopes is roughly twice the size of the handwriting on the Senate letter and envelopes. The envelopes addressed to Senators Daschle and Leahy had a fictitious return address:
4th Grade
Greendale School
Franklin Park NJ 08852
Franklin Park, New Jersey, exists, but the ZIP Code 08852 is for nearby Monmouth Junction, New Jersey. There is no Greendale School in Franklin Park or Monmouth Junction, though there is a Greenbrook Elementary School in adjacent South Brunswick Township, New Jersey.
False leads
The Amerithrax investigation involved many leads which took time to evaluate and resolve. Among them were numerous letters which initially appeared to be related to the anthrax attacks but were never directly linked.
For example, before the New York letters were found, hoax letters mailed from St. Petersburg, Florida, were thought to be the anthrax letters or related to them. A letter received at the Microsoft offices in Reno, Nevada, after the discovery of the Daschle letters, gave a false positive in a test for anthrax. Later, because the letter had been sent from Malaysia, Marilyn W. Thompson of The Washington Post connected the letter to Steven Hatfill, whose girlfriend was from Malaysia. The letter merely contained a check and some pornography, and was neither a threat nor a hoax.
A copycat hoax letter containing harmless white powder was opened by reporter Judith Miller in The New York Times newsroom.
Also unconnected to the anthrax attacks was a large envelope received at American Media, Inc., in Boca Raton, Florida (which was among the victims of the attacks), in September 2001. It was addressed "Please forward to Jennifer Lopez c/o The Sun", containing a metal cigar tube with a cheap cigar inside, an empty can of chewing tobacco, a small detergent carton, pink powder, a Star of David pendant, and "a handwritten letter to Jennifer Lopez. The writer said how much he loved her and asked her to marry him." Another letter, which mimicked the original anthrax letter to Senator Daschle, was mailed to Daschle from London in November 2001, at a time when Hatfill was in England, not far from London. Shortly before the discovery of the anthrax letters, someone sent a letter to authorities stating, "Dr. Assaad is a potential biological terrorist." No connection to the anthrax letters was ever found.
During the first years of the FBI's investigation, Don Foster, a professor of English at Vassar College, attempted to connect the anthrax letters and various hoax letters from the same period to Steven Hatfill. Foster's beliefs were published in Vanity Fair and Reader's Digest. Hatfill sued and was later exonerated. The lawsuit was settled out of court.
Anthrax material
The letters sent to the media contained a coarse brown material, while the letters sent to the two U.S. Senators contained a fine powder. The brown granular anthrax mostly caused cutaneous anthrax infections (9 out of 12 cases), although Kathy Nguyen's case of inhalational anthrax occurred at the same time and in the same general area as two cutaneous cases and several other exposures. The AMI letter which caused inhalation cases in Florida appears to have been mailed at the same time as the other media letters. The fine powder anthrax sent to Daschle and Leahy mostly caused the more dangerous form of infection known as inhalational anthrax (8 out of 10 cases). Postal worker Patrick O'Donnell and accountant Linda Burch contracted cutaneous anthrax from the Senate letters.
All of the material was derived from the same bacterial strain known as the Ames strain. The Ames strain is a common strain that was isolated from a cow in Texas in 1981. The name "Ames" refers to the town of Ames, Iowa, but was mistakenly attached to this isolate in 1981 because of a mix-up about the mailing label on a package. First researched at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID), at Fort Detrick, Maryland, the Ames strain was subsequently distributed to sixteen bio-research labs within the U.S., as well as three international locations (Canada, Sweden and the United Kingdom).
DNA sequencing of the anthrax collected from Robert Stevens (the first victim) was conducted at The Institute for Genomic Research (TIGR) beginning in December 2001. Sequencing was finished within a month and the analysis was published in the journal Science in early 2002.
Radiocarbon dating conducted by Lawrence Livermore National Laboratory in June 2002 established that the anthrax was cultured no more than two years before the mailings.
Mutations
Early in 2002, an FBI microbiologist noted that there were variants or mutations in the anthrax cultures grown from powder found in the letters. Scientists at TIGR sequenced the complete genomes from 21 of these isolates during the period from 2002 to 2004. The bioinformatics scientists at TIGR, including Steven Salzberg, Mihai Pop, and Adam M. Phillippy, identified three relatively large changes in some of the isolates, each comprising a region of DNA that had been duplicated or triplicated. The size of these regions ranged from 823 to 2607 base pairs, and all occurred near the same genes. Details of these mutations were published in 2011 in the Proceedings of the National Academy of Sciences. These changes became the basis of polymerase chain reaction assays used to test other samples to find any that contained the same mutations. The assays were validated over the many years of the investigation, and a repository of Ames samples was also built. From roughly 2003 to 2006, the repository and the screening of the 1,070 Ames samples in that repository were completed.
Controversy over coatings and additives
On October 24, 2001, United States Army Medical Research Institute of Infectious Diseases (USAMRIID) scientist Peter Jahrling was summoned to the White House after he reported signs that silicon had been added to the anthrax recovered from the letter addressed to Daschle. Silicon would make the anthrax more capable of penetrating the lungs. Seven years later, Jahrling told the Los Angeles Times on September 17, 2008, "I believe I made an honest mistake,” adding that he had been "overly impressed" by what he thought he saw under the microscope.
Richard Preston's book The Demon in the Freezer provides details of conversations and events at USAMRIID during the period from October 16, 2001, to October 25, 2001. Key scientists described to Preston what they were thinking during that period. When the Daschle spores first arrived at USAMRIID, the key concern was that smallpox viruses might be mixed with the spores. "Jahrling met [John] Ezzell in a hallway and said, in a loud voice, 'Goddamn it, John, we need to know if the powder is laced with smallpox'". Thus, the initial search was for signs of smallpox viruses. On October 16, USAMRIID scientists began by examining spores that had been "in a milky white liquid" from "a field test done by the FBI's Hazardous Materials Response Unit”. Liquid chemicals were then used to deactivate the spores. When scientists turned up the power on the electron beam of the Transmission Electron Microscope (TEM), "The spores began to ooze". According to Preston,